Is your feature request related to a problem? Please describe.
Everywhere where Apple offers it, I use Apple's Private Relay e-mail addresses.
However, they can't be manually generated, so for the rest, I use https://anonaddy.me. Because it offers infinite aliases, I use a different alias every time I give my e-mail address to someone. However, I ensure that they're all under the @rokejulianlockhart.anonaddy.com (.com and .me are equivalent in this case) domain so that they can be identified as me by a human. I use different aliases to combat spam, not be anonymous.
Additionally, when messaging others, I ensure that I add a sub-address with my name to their e-mail address so that they can filter all messages from me (even if I'm using a different alias for my own filtering purposes). Others use the same when communicating with me, especially family. The current identification system doesn't take sub-addresses into account whatsoever.
Describe the solution you'd like
I should therefore be able to set
RY7I0I+RY7I0R@rokejulianlockhart.anonaddy.com as an e-mail address, and beneath it add, for instance
[A-Za-z0-9]+\+[A-Za-z0-9]+@rokejulianlockhart\.anonaddy\.com
in another input form to ensure that Nextcloud identifies any (in this case sub-addressed) alias as me.
Describe alternatives you've considered
The sole current alternative is to list literal tens of thousands of aliases as myself, which is insane. It also wouldn't work, because https://anonaddy.me generates a new alias when someone else uses one, so I'd have to retroactively add those whenever someone else uses one. It also wouldn't account for sub-addresses.
Additional context
Like most more powerful features of Nextcloud, this only need be visible when clicked on. Adding a button beside each e-mail address to show a form which allows the user to enter custom regex is enough.
Additionally requested at:
- https://feedbackportal.microsoft.com/feedback/idea/ed4261f8-af28-ee11-a81c-6045bd8534ad.
- https://discussions.apple.com/thread/255016441.
- https://github.com/nextcloud/contacts/issues/3530#issue-1816825315.
